PROJECT OBJECTIVES: It is planned to determine the type and numbers of glycoprotein moieties present in islet membranes by studying the binding characteristics of a variety of lectins to intact islets. This data will be correlated with the functional characteristics of freshly prepared and incubated islets. Incubated islets will also be used in a modified mixed-lymphocyte culture procedure in an attempt to determine why incubated islets are less immunogenic than freshly prepared tissues. The second part of this proposal will examine the mechanisms involved whereby the pretransfusion of recipient rats with specific donor blood leads to a delayed rejection of transplanted islets. We are particularly interested in the blood component responsible for these results.